1. Field of the Invention
The present invention relates to the obtaining of data from radio frequency identification (RFID) tag devices.
2. Background Art
Radio frequency identification (RFID) tags are electronic devices that may be affixed to items whose presence is to be detected and/or monitored. The presence of an RFID tag, and therefore the presence of the item to which the tag is affixed, may be checked and monitored by devices known as “readers.” Readers typically transmit radio frequency signals to which the tags respond. Each tag can store a unique identification number. The tags respond to the reader transmitted read signals by providing their identification number, bit-by-bit, so that they can be identified.
Tags sometimes fail to respond to read requests for various reasons, including defects or damage to the tags. In such situations, it may be necessary for a human operator to hand-enter data printed on the failed tag into a system so that the tag can be identified. However, such a backup system for failed reads of tags is inefficient. For example, the full serialized identifier provided by EPC RFID tags requires at least 30 digits to be represented in human-readable form. Entering in such long strings of data by hand is error prone and time consuming. Thus, the hand-entering in of printed data from a tag is not necessarily a reliable or cost-effective backup system for read failures.
Some tags have barcodes associated with them for backup to failed tag reads. For such a tag, the barcode is scanned while the tag is read. If the tag fails to respond to a read request, the scanned barcode information can be used to identify the tag. However, such an implementation has inefficiencies. For example, a large amount of power is required to both read a tag and scan a barcode each time a tag is desired to be identified. An increase in data transmission traffic occurs when duplicate data resulting from a successful tag read and barcode scan is decoded. Furthermore, mismatched information can result when a tag that responds to a read signal is different from the tag having its barcode scanned.
Thus, what is needed is a more efficient, reliable, and cost-effective backup identification system for failed tags.